Magnetic coding apparatus



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IN V EN TOR.

J. J. SAYKAY 2 Sheets-$heet 1 J. J SAYKAY MAGNETIC CODING APPARATUS Nov. 8, 1966 Filed April 2, 1963 Nov. 8, 1966 J. J. SAYKAY 3,284,773

MAGNETI C GODING APPARATUS Filed April 2. 1963 2 Sheets-Sheet 2 FIG; 2

INVENTOR.

J. J. SAYKAY United States Patent O MAGNETIC CODIN G APPARATUS Joseph John Saykay, Sea Clii, N.Y., assignor to Fairchild Camera and Instrument Corporation, a corporation of Delaware Filed Apr. 2, 1963, Ser. No. 270,055 6 Claims. (Cl. 340-147) This invention relates in general to coding apparatus. While it is of general utility and has general application it is particularly `suitable for use with a key operated machine such as a typewriter to provide a code representation of information selected at the keyboard in a form suitable for storage, transmission or the like. In the description, the invention will be described as it might be used in such an application. l

The prior art has taught that coding devices of various types may be used with an ordinary typewriter to provide a punched tape or other output suitably coded to be used to operate automatic devices such as an automatic typesetting machine. One form of coding device suitable for such use is described and claimed in United States Patent 3,065,298 assigned to Fairchild Camera and Instrument Corporation, the assignee ofl the instant invention. v

The novel coding device described' in that patent permits not only alpha-numeric information but also information as to type widths in vari-ous increments to be translated into coded punched tape by means of a code matrix using a minimum number of diodes. This results in a saving in cost as well as mitigating the problem of reverse leakage current encountered in such apparatus when a large number of diodes are connected in parallel. Alternatively, coding devices could be used with a machine such as a tape perforator, etc., providing pattern of signals in a predetermined code which,v

in turn, 4may be used to control a typewriter.

While the subject matter of United State Patent 3,065,298 has proven acceptable in actual usage, certain problems still remain in some applications despite the many advantages it provides. lected diode in the matrix carries full load current which, under certain conditions could cause arcing at the switch contacts; leakage or reverse current through non-selected diodes, though substantially reduced, is `still present; 64 double switches, one for each of the 64 valid combinations possible, are required which, in addition t-o the cost consideration, increases the touch or force required to be exerted at the keyboard.

Accordingly, it is an object of the invention to provide a new and improved coding apparatus.

It is another object of the invention to providea new and improved coding .apparatus in which the disadvantages of the prior art are avoided.

Briefly stated, in accordance with t-he invention a coding apparatus comprises a plurality of banks of units, all but one unit in each b ank including at least -one contact pair having a normal condition and also actuating means responsive to the passage of current therethrough to temporarily change the normal condition of the contact pairs in its unit. The remaining unit in each bank is an impedance. Means are further provided for establishing a circuit including one of the actuating means or the impedance from each bank. A corresponding contact of all the contact pairs is connected to one of a .plurality of output lines associated with each bank .in

is had to the following description taken in connection 'For example, each sey with the accompanying drawing, while its scope will be pointed -out with particularity in the appended claims.

In the drawing:

FIGURE 1 is a schematic representation of a coding apparatus embodying the invention;

FIGURE 2 is a schematic representation of a modiiication of the apparatus shown in FIGURE 1.

Referring now to FIG. 1 the coding apparat-us shown therein includes two banks Q and 1g of units respectively controlling output lines 13-15 and 16-18. There`are eight input conductors 19-26 and 27-34 associated respectively 4with banks Q and 1 2. All but one -unit in each bank includes a switch actuating element shown vin the embodiment as magnetic field-producing coils or electromagnetic relays 35u-48a, one associated with each of conductors 19-34, and one or more single-pole switches yor contact pairs 35b-48b associated with each coil. Coils 35a-41a associated with lines 19-26 have one end con- Ynected to a source of potential 49 which may be'of any identilied as elements 51 and 52 and respectively, each connected in a manner. identical to the coils in their associated banks. Dummy units 51 and 52 are used to enable the production of those output patterns which require the absence of a signal at any of the output conductors associatedwith one or both of banks 1 1 and 1g. Preferably, each of dummy units 51 and 52 is a resistor having a value equal to t-he resistance of one of coils 35u-48a. Alternatively, any desired dummy unit may be a unit identical to any of units 35u-351), 36a- 36b 48a-48b. In such case the contact pairs of the units used in place of dummy units 51 and S2 would not be connected to any output line.

A plurality of other single-pole switches are provided of which two are identified by numerals 53 and 54. In 'a typical embodiment such as that discussed in the introduction, they eight input conduct-ors in each of banks Q and 1g enable the selection of sixty-four different combinations of two conductors, one from eac-h bank. Sixty-four single-pole switches may then be used'as illustrated, each of the type identified by numerals 53 and 54, `and each connecting'a different pair of conductors, one from the group containing lconductors 19-26, the other from the group containing conductors 27-34. When any one of the sixty-four switches is closed, as for example, by selection of a keyV on a typewriter keyboard, a circuit is established which includes a unique pair of actuating coils, one from bank 1 1 and the other from bank 1 2. For example, when switch 54 is closed a path is provided from potential source 49 through coil 35a, conductor 20, switch 54, conductor 34 and coil 48a to the reference potential point 50. The potential impressed across the pairv of elements thus selected, one of coils 35a-41a or dummy unit 51, and one of coils 4261-4861 or dummy unit 52, results in a current flow through the circuit and the provision of a magnetic field by each coil included in the pair of elements selected.

The coding apparatus illustrated has six output conductors 13-18 which might, for example, be connected to the actuators of six punches or to any other desired load. Output conductors 13-15 are associated with the switches or contact pairs included in bank 1 1 and output conductors 16-18 are associated with tli-eswitches or contact pairs included in bank 12; In this embodiment each Vswitches associated with any selected coil.

of switches 35b-48b includes at least one and as many as three contact pairs which may be of the so-called reed or glass reed variety. In the embodiment illustrated each of these switches includes a pair of contacts, the

'contacts of switch 43b being identified by reference numerals 55 and 56. Of course, here need be no switches associated with dummy units 51 and S2.

The contact of each of switches 35be48b corresponding to contact 55 of switch 43b is connected to a source of potential 57 which may have a value the same as or diierent than that of source 49 depending upon the particular application of the apparatus. In this embodiment source 57 is also shown as the positive terminal of a Battery the other terminal of which is returned to a source of reference potential or ground.

The other contact of each of switches 35b-41b is connected to one of output conductors 13-15 and the other contact of each of switches 42h-48h is connected to one of output conductors 16-18 all in accordance with -a predetermined code. It will be noted that where more than one contact pair or switch is associated with a single coil, e.g. coil 41a which has three contact pairs or switches 35h associated therewith, each of the switches so associated is connected to a separate output line, in accordance with the predetermined code.

In the embodiment shown, passage of current through any selected pair of elements (coils 35u-48a and dummy units 51 and 52) by actuation of selected key-actuated switches 53, 54, etc., will close the contacts of all the It is clear, of course, that the -coding apparatus could operate equally Iwell were it arranged so that switches 35b48b were normally closed and were selectively opened by passage of 'current through associated coils and similary the switches `can only pass through a pair of coils, one from bank Il and .one from bank 1g, but the identical pattern is ob:

servable on output cductors 16-18 when any one of coils 42a-48a or dummy unit 52 has current pass therethrough and consequently the abbreviated table is sufficient. the normal signal condition of the output conductor, in

Lthis embodiment when all switches connected to that line are open, and the symbol 17 is used to indicate the change in signal condition of the output conductor when a switch connecting potential source 57 thereto is closed.

OUTPUT CONDUCTORS In the table, the symbol is used to indicate 4261-486 or dummy s2 from bank 1 2 Eiy one of 26 or 64 distinct and unique patterns of signals-may be provided on the 6 output lines 13-18. In addition, the apparatus for doing this, the cir-cuit shown in FIG. l accomplishes this with only 64 single switches (to connect one of lines 19-26 with one of lines 27-34) and only 14 reed switch units 35a-35b, 36u-36h etc. It should also be noted that the selection is made through control circuitry which is not physically connected to the matrix and output lines. This disjunction, in addition to other advantages, permits virtually complete freedom in selecting optimum voltage and current output levels for any particular application, which levels may be different from the level of the control signals applied to the glass reed switch actuating elements, i.e. coils 35a-48a.

The circuit shown in FIG. l could be expanded to permit combinations in excess of 64 by increasing the number of banks of units, in a manner similar to that discussed in Patent 3,065,298. Of course, were expansion accomplished in that manner then switches 53, 54 etc. would have to be ofthe multiple contact type.

A preferred method of increasing the number of available code combinations is to increase the number of units in each bank, at the same time increasing the maximum number of single-pole switches or contact pairs that a given unit must handle.

For a two bank apparatus the relationship between input conductors, output conductors, bank units, the maxi- -mum number single-pole switches or contact pairs any unit must have, and the numlber of available code cornbinations is as follows:

w=nuan=ber of output conductors in rst bank. vsc=number of output conductors in second bank. w=maximum number of singledpole switches or contact pairs any unit in first bank must have. x=maxmum number of single-pole switches or contact pairs any unit in second bank must have. y=number of input conductors i-n rst bank. z=number of input conductors in second bank. yz=number of code combina-tions available. (yz*l=number of usable code combinations.) y-1=number of units in one :bank plus one dummy unit. z-1=number of units in second ibank plus one dummy unit.

The relationships then are as follows:

The number of code combination representable is equal to the product of the number of input conductors in each bank, or to the value of 2 raised to a power equal to the total number of output conductors. That is, the maximum number of possible code combinations using 15 14 13 `a straight binary code is equal to yz or ZW-l-x whichever is less.

In a symmetrical arrangement, w=x, y=z, and Dummy 51 0 0 0 W+X` 2 n Coil 35 0 0 1 yz=2 or y =2 where n=2w=2x. In this case no 8 g 60 unit in a bank would have to include more than 11/2 single- Coi13sa 1 o 0 pole switches or contact pairs. gggg: (l) (l) The following talble shows a typical sequence of ex- Coi141a 1 1 1 pansions, the last example permitting 4,0496 separate code combinations to be represented:

Number of Output Con- Total Number Units ductors and/or Maximum Number of Input Maximum in Each Bank Number of Switches Any Conductors Each Code No. Excluding Two Unit Must Have in Each Bank Dummys Bank 3:3 8:8.- 64 14. 4:6 16:6 12s 22. 4:4 16:16 256 30. 5:4 32:16 612 46. 5:6 32:22 m24 -v 62. 6:6 64:32 204s 94. 6:6 64:64 4096 126. wn: y:z 2v+ or Wx..- y-i-z-2 In FIG. -2 structure which is the-same as structure in FIG. l has the same reference numeral as its counterpart,

differing by 100. This figure has lbeen simplified by omitting, for example, all but two switches 153 and 154. Thus bank 1 1 of FIG. 1 corresponds to bank 111 of FIG. 2 and coil 35a of FIG. 1 corresponds to coil 135a of FIG. 2. Basically, the -theory behind, and the operation of this construction is theysame as that illustratedyi'n FIG. l.

The primary difference between the embodiment of FIG. l and that of FIG. 2 is that both elements comprising each switch unit, actuating means `or coil and contact pair, is connected at one end to the same source of potential. Thus, one end of each lof coils 13Sa-141a in bank 111 is connected to potential source 20)k shown as the positive terminal of a battery, the other terminal of which is connected to a source of reference potential or ground. One of each of the contact pairs constituting the switches 135b-141b associated with coils 135a-141a is also connected to potential source 200. Similarly, one end of coils 142a-148a in bank 112 is connected to potential source 201 which has a value different than the value of potential source 200, shown here as the negative terminal of a battery, the other terminal of which is connected to a source of reference potential. Here again, one of each of the contact pairs in this bank is connected to potential source 201, the other one of each of the contact pairs being connected to one of output lines 113-118 as was the case with the embodiment shown in FIG. 1.

The tables set forth above are valid for the embodiment of FIG. 2. It will be appreciated that in this embodiment too, there is no problem of reverse current flow, etc.

While there has been described what is at present iconsidered to be the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is, therefore, aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of this invention.

What is claimed is:

1. A coding apparatus comprising a plurality of banks of units, all but one of said units in each of said banks including at least one contact pair having a normal condition and actuating means responsive lto the passage of current therethrough for temporarily ichanging the normal condition of the con-tact pairs included in that unit, the other unit in each of said banks comprising an impedance, a current-supply circuit for said actuating means, means for establishing a circuit including said current-supply circuit and any chosen pair of said actuating means and said impedances, each from a different one of said banks, a plurality of output conductors associated with each of said banks, a corresponding contact of all of said contact pairs being connected to said output conductors associated with their respective -banks in accordance with a predetermined code, current-supply circuit for said output conductors, the other contact of all -of said contact pairs bein-g connected to said current-supply circuit for said output conductors.

2. A coding apparatus comprising at least a first and second bank of units, said first bank having w units, said second bank having x units, all but one of said units in each bank including an electromagnetic relay having at least one contact pair associated therewith, said other unit in each of said banks comprising an impedance, a first current supply circuit, w-x switches each operable to establish a circuit including said rst current supply circuit and any chosen one of said electromagnetic relays or said impedance from each of said banks of units, y output conductors associated with said first bank of units, z output conductors associated with said second bank of units where 2Y+Z=wx, a second current supply circuit, a corresponding contact of all of said contact pairs being connected to said output conductors associated with their respective banks in accordance with a predetermined code, the other contact of all of said contact pairs being connected to said second current supply circuit.

3. A coding apparatus comprising at least a first and a second bank, said first bank having wl electromagnetic relays, said second bank having x-l electromagnetic relays, an impedance in each of said banks, a first currentsupply circuit, wx switches each operable to establish a circuit including said first current-supply circuit and any chosen one of said electromagnetic relays or said impedance from each of said banks of units, y output conductors associated with said first bank of units,'z output conductors associated with said second bank of units Where 2Y+Z= wx, at least one and as many as y contact pairs operable by each relay in said first bank, at least one and as many as z contact pairs associated with and operable by each relay in said second bank, a second current supply circuit, a corresponding contact of all of said contact pairs being connected to said output conductors associated with their respective banks in accordance with a predetermined code, the other contact of all of said contact pairs being connected to said second current supply circuit.

4. A coding apparatus comprising at least a first and a second bank, said first bank having w-l electromagnetic relays, said second bank having x-l electromagnetic relays, an impedance in each of said banks, a plurality of current-supply circuits, wx switches each operable to establish a circuit including first and second ones of said current supply-circuits and a chosen one of said electromagnetic relays or said impedance from each of said banks of units, y output conductors associated with said first bank of units, z output conductors associated with said second bank of units where 2Y+Z=wx, at least one and as many as y contact pairs associated with and operable by each relay in said first bank, at least one and as many as z contact pairs associated with and operable by each relay in said second bank, a corresponding Contact of all of said contact pairs being connected to said output conductors associated with their respective banks in accordance with a predetermined code, the other contact of all of said contact pairs in each of said banks being connected to third and fourth ones of said supply circuits respectively.

5. A coding apparatus comprising at least a first and a second bank, said first bank having w-l electromagnetic relays, said second bank having x-l electromagnetic relays, an impedance in each of said banks, a first and second current-supply circuits, wx switches each operable to establish a circuit including first and second ones of said current-supply circuits and a chosen one of said electromagnetic relays or said impedance from each of said banks of units, y output conductors associated with said first bank of units, z output conductors associated with said second bank of units where 2Y+Z= wx, at least one and as many as y contact pairs associated with and operable by each relay in said first bank, at least one and as many as z contact pairs `associated with and operable by each relay in said second bank, a corresponding contact of all of said contact pairs being connected to said output conductors associated with their respective banks in accordance with .a predetermined code, the other contact of :all of said contact pairs in each of said banks being connected to said first and second supply circuits respectively.

6. A coding apparatus comprising at least a first and a second bank, said first bank having w-l electromagnetic relays, said second bank having x-l electromagnetic relays, an impedance in each of said banks, a first currentsupply circuit, wx switches each operable to establish a circuit including said first current-supply circuit, a chosen one of said electromagnetic relays or said impedance from each of said banks of units, and ground, y output conductors associated with said first bank of units, z output 7 conductors associated with said second bank of units where 2Y+Z=wx, at least one and as many as y contact pairs associated with and operable by each relay in said rst bank, at least one and as many as z contact pairs associated with and operable by each relay in said second bank, a second current supply circuit, a corresponding contact of all of said contact pairs being connected to said output conductors associated with their respective banks `8 in accordance with a predetermined code, the other contact of 'all of said contact pairs being connected to a second one of said current-supply circuits.

No references cited.

NEIL C. READ, Primary Examiner.

,THOMAS A. ROBINSON, Examiner. 

1. A CODING APPARATUS COMPRISING A PLURALITY OF BANKS OF UNITS, ALL BUT ONE OF SAID UNITS IN EACH OF SAID BANKS INCLUDING AT LEAST ONE CONTACT PAIR HAVING A NORMAL CONDITION AND ACTUATING MEANS RESPONSIVE TO THE PASSAGE OF CURRENT THERETHROUGH FOR TEMPORARILY CHANGING THE NORMAL CONDITION OF THE CONTACT PAIRS INCLUDED IN THAT UNIT, THE OTHER UNIT IN EACH OF SAID BANKS COMPRISING AN IMPEDANCE, A CURRENT-SUPPLY CIRCUIT FOR SAID ACTUATING MEANS, MEANS FOR ESTABLISHING A CIRCUIT INCLUDING SAID CURRENT-SUPPLY CIRCUIT AND ANY CHOSEN PAIR OF SAID ACTUATING MEANS AND SAID IMPEDANCES, EACH FROM A DIFFERENT ONE OF SAID BANKS, A PLURALITY OF OUTPUT CONDUCTORS ASSOCIATED WITH EACH OF SAID BANKS, A CORRESPONDING CONTACT OF ALL OF SAID CONTACT PAIRS BEING CONNECTED TO SAID OUTPUT CONDUCTORS ASSOCIATED WITH THEIR RESPECTIVE BANKS IN ACCORDANCE WITH A PREDETERMINED CODE, CURRENT-SUPPLY CIRCUIT FOR SAID OUTPUT CONDUCTORS, THE OTHER CONTACT OF ALL OF SAID CONTACT PAIRS BEING CONNECTED TO SAID CURRENT-SUPPLY CIRCUIT FOR SAID OUTPUT CONDUCTORS. 